query(p29,w(0),[w(0),u(0)],[w(0)],[]).
%-----------------------------------------------------------

:- table u / 1.
:- table w / 1.

e(s(0),s(s(0))).
e(s(0),0).
e(s(A),s(s(A))) :- e(A,s(A)).
e(s(A),0) :- e(A,0).
w(A) :- tnot(u(A)).
w(A) :- e(B,A), tnot(w(B)).
u(0) :- fail.
